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This section contains lists of the contaminants of concern. However, inclusion on the list doesnot imply that a contaminant represents a threat to public health. Subsequent sections of thisHealth Assessment will evaluate these contaminants of concern to determine if exposure to themhas public health significance. ATSDR selects these contaminants based upon the followingfactors:

  1. Concentrations of contaminants on and off site.
  2. Field data quality, laboratory data quality, and sample design.
  3. Comparison of site-related concentrations with health assessment comparison (HAC) valuesfor (1) non-carcinogenic endpoints and (2) carcinogenic endpoints.
The data tables and text that follow include the following acronyms and symbols:* BEHP = Bis(2-ethylhexyl)phthalate

* EMEG = Environmental Media Evaluation Guide

* NCREG = Non-carcinogenic Risk Evaluation Guide

* CREG = Carcinogenic Risk Evaluation Guide

* TCDD = 2,3,7,8 Tetrachlorodibenzo-p-dioxin

* PAHs = Polycyclic Aromatic Hydrocarbons

* PCBs = Polychlorinated Biphenyls

* RfD = Reference Dose

* TCE = Trichloroethylene

* MRL = Minimal Risk Level

* CSF = Cancer Slope Factor

* ppm = parts per million

* ppb = parts per billion

* µg/L = Micrograms Per Liter (equal to parts per billion)

* mg/kg = Milligrams Per Kilogram (equal to parts per million)

* mg/L = Milligrams Per Liter (equal to parts per million)

* µg/m3 = Micrograms per Cubic Meter of Air

Health assessment comparison (HAC) values are contaminant concentrations for specific mediathat are used to select contaminants for further evaluation. Exceeding a HAC value does notimply that a contaminant represents a threat to public health. These values include NCREGs andCREGs. NCREGs are HAC values based on non-carcinogenic risk and are calculated eitherfrom ATSDR's MRLs, USEPA's RfDs, or other relevant health guidelines. CREGs are HACvalues based on the risk of one excess cancer in a million persons exposed over a lifetime.

In this report, dioxins (chlorinated dibenzodioxins) and furans (dibenzofurans) are expressed as2,3,7,8-TCDD equivalents (TCDDe). To calculate TCDD equivalents the concentration of eachdioxin/furan is multiplied by its respective relative potency factor. This yields a concentrationrepresentative of the compound's toxicity when compared to 2,3,7,8-TCDD, the most toxic form. To develop the total TCDDe, all the TCDD equivalents are summed. While this proceduremakes several assumptions with regard to toxicity and summation of toxic effects, it is anapproach that weighs on the side of public health.


The data presented in this subsection were collected for the Texas Department of WaterResources, the Texas Water Commission, and the USEPA by IT Corporation (IT), in associationwith Environmental Research and Technology, Inc. (ERT), and Rollins Environmental Services(Texas), Inc. (Rollins) during the summer of 1984 (Reference 2). Previously, soil andgroundwater samples had been analyzed for PCBs by Ecology and Environment in September,1982 (Reference 2). In November 1984 samples were analyzed for dioxins. Air quality data wascollected by the Texas Air Control Board in November, 1983, and by IT, ERT, and Rollins in thesummer of 1984.

Waste Residue

Six samples of waste residues were collected from six tanks on the site. Contaminants in thesesamples which exceeded HAC values included PCBs, BEHP, and 2,3,7,8 TCDDe. HAC valueswere not available for many of the Polycyclic Aromatic Hydrocarbons. The results of theseanalyses are presented in Table 1. These materials have since been removed from the site.

Table 1.

Geneva Industries Waste Residue Contaminants of Concern
ChemicalDate SampledMaximum
Conc. (mg/kg)
LocationHAC VALUES (mg/kg)Source
Total PCBs6/8428,700RES-20.250.09EMEG/CSF
Polycyclic Aromatic Hydrocarbons
3, 4 Benzofluoranthene and/ or benzo(k)fluoranthene*6/8465RES-2NANANA
Chlorinated Dibenzo Dioxins and Furans

NA = No HAC values available.
*Isomeric pairs

Test Pits

Ten test pits were excavated in areas where waste was expected to be buried. Between one andsix samples were taken from each test pit; most of the 35 samples analyzed were composites. The method of compositing was not reported. Depths of sampling ranged between 0 to 8 feetbelow the land surface, depending upon the depth at which soil appeared to be contaminated. PCBs and TCDDe were found at levels above HAC values (Table 2). These materials have sincebeen removed from the site.

Table 2.

Geneva Industries Test Pits (On-site) Contaminants of Concern
Chemical Date Sampled Sample Depth
Maximum Conc.
Location HAC VALUES (mg/kg) Source
Total PCBs 8/84 0-1 1,770 TP-10, S-1 0.25 0.09 EMEG/CSF
Polycyclic Aromatic Hydrocarbons
Chrysene 8/84 0-1 24.0 TP-4, S-1 NA NA NA
Phenanthrene 8/84 0-1 8.2 TP-10, S-1 NA NA NA
Chlorinated Dioxins/Furans
TCDDe 8/84 0-1 0.000057 TP-10, S-1 0.00005 0.0000047 EMEG/CSF

NA = No HAC values available

On-site Soil

On-site surface and subsurface soils were contaminated by operational spills, leaking drums,tanks, and lagoons, landfill, and possible landfarming operations. The contaminants identified inthe on-site soils are the expected process products and waste residues associated with formerplant operations.

Samples of soil at a specified depth of 0 to 6 inches were collected from eight locations. Thesewere collected and tested in June, 1984 to supplement existing soil data collected by USEPA in1982. Two of the samples (SS-1 and SS-2), from areas covered by the surface cap, were taken ata depth of 0-6 inches below the surface cap. Ten shallow soil boring samples (8 feet and 14 feet)were collected. Deep soil boring samples were taken during the installation of five monitor wellsand the soil beneath the waste pond was sampled. Table 3 contains the contaminants of concernin the soil; Figure 5 shows the soil sampling locations. PCBs and TCDDe exceeded HAC values in this media . These soils have been removed from the site.

Table 3.

Geneva Industries
On-site Soil
Contaminants of Concern
ChemicalDate SampledSample DepthMaximum Conc.
LocationHAC VALUES (ppm)Source
Total PCBs11/84 0-6"10.0SS-40.250.09EMEG/CSF
7/841'-2'364B-5, S-10.250.09EMEG/CSF
Polycyclic Aromatic Hydrocarbons
Phenanthrene7/849.5'-10.5'32PB-1A, C-6NANANA
Chlorinated Dibenzodioxins and Furans
TCDDe 11/840.000258NA0.000050.0000047EMEG/CSF

NA = No HAC Values Available

On-site Sediment

Eight sediment samples were taken from the drainageways on site. Figure 4 shows site drainagepatterns prior to remediation. Due to the temporary cap on the site, PCB concentrations insediments from on-site drainageways were generally below 1.0 ppm except for SD-16, adrainageway on the southeast portion of the site, which had PCBs at 684 ppm (Table 4). PCBsdownstream of this sampling location ranged from "non-detectable (ND)" to 4 ppm. Prior tosource control remediation, on-site sediment samples contained PCBs at levels exceeding HACvalues.

Table 4.

Geneva Industries Contaminants of Concern Sediment Sampling
Chemical Date Sampled Sample Depth Maximum Conc.
Location HAC VALUES (ppm) Source
Total PCBs 7/84 0-3" 684 SD-16 0.25 0.09 EMEG/CSF
Acenaphthylene 7/84 0-3" 3.9 SD-17 NA NA NA
Chrysene 7/84 0-3" 7.8 SD-17 NA NA NA
Total PCBs 7/84 Grab Sample 4 SD-9 0.25 0.09 EMEG/CSF
Benzo(a)pyrene 7/84 Grab Sample 0.49 SD-8 NA NA NA
Benzo (k) fluoranthene 7/84 Grab Sample 2.1 SD-8 NA NA NA
Chrysene 7/84 Grab Sample 11 SD-8 NA NA NA
Phenanthrene 7/84 Grab Sample 28 SD-8 NA NA NA

NA = No HAC Values Available

On-site Surface Water (Stormwater)

Because no storm event resulting in significant site runoff occurred during the field operation,stormwater samples were limited to grab samples of standing water as available. In July of 1984three samples were collected from standing water in the three on-site drainage ditches and threesamples were from areas of localized ponding on the site. The results of sample analyses aresummarized in Table 5. Prior to source control remediation, levels of PCBs exceeded HACvalues in all three samples collected from the ponded water and in the standing water from theon-site drainage ditch on the south end of the site.

Table 5.

Geneva Industries Contaminants of Concern
On-site Surface Water (Stormwater)
ChemicalDate SampledSample DepthMaximum Conc.
LocationHAC VALUES (ppb)Source
Total PCBs7/84Grab Sample158SW-10.050.0045EMEG/CSF

On-Site Groundwater

Thirteen groundwater monitoring wells (MW) were installed on site. Nine were screened in the30-foot sand and four were screened in the 100-foot sand. Water samples were taken from thesewells following purging. Contaminants of concern exceeding HAC values in the 30-foot sandincluded: PCBs, ethylbenzene, benzene, mercury and TCDDe. The highest concentrations werefound in MW-4 and MW-5 which are located near the center of the site. In the 100-foot sandPCBs and TCE concentrations exceeded HAC values. The results are summarized in Table 6.

Table 6.

Geneva Industries Contaminants of Concern On-site Groundwater
ChemicalDate SampledSample Depth
Maximum Conc.
LocationHAC VALUES (ppb)Source
Total PCBs11/843010,000 MW40.050.0045EMEG/CSF
Volatile Organic Compounds
Ethylbenzene7/84301,500 MW41000.0NARfD
Polycyclic Aromatic Hydrocarbons
Naphthalene7/843096 MW4NANANA
Chlorinated Dioxins/Furans
TCDDe 11/84300.314 MW40.000050.0000047EMEG/CSF

NA = No HAC values available

On-Site Air Quality

In 1983, during USEPA's planned removal activities, the Texas Air Control Board and USEPAcollected air samples on-site, upwind, and downwind at the property line of the Genveva site. Samples were collected and analyzed to determine if PCBs, disturbed at the site during theremoval activities, were becoming airborne, thereby affecting the local air quality. Air qualityresults are reported in Table 7. Additional air samples were collected and analyzed for PCBs andasbestos in June and July of 1984. One sample was collected upwind of the site and two sampleswere collected at two different locations downwind of the site. All measurements were belowdetection limits. No data on PCBs were reported from the work area.

Table 7.

Geneva Industries On-site Air Sampling
ChemicalSample DateMaximum Conc.LocationHAC VALUES Source
PCBs11/832.16 µg/m3**
3.94 µg/m3**
30.53 µg/m3**
Upwind/Site 3
Downwind/Site 2
On-site/Site 4
Upwind 1
Downwind 1
Downwind 2
Asbestos7/84<2 fibers/m3*Upwind 1
Downwind 1
Downwind 2
NA0.0000043µg/m3Inhalation Cancer Risk

* < Below detection limit
** Conversion from ppb to µ/m3 using an average molecular weight of 311.
NA = No HAC values available



Two off-site soil samples were taken east of the Flood Control Channel and one off-site samplewas taken west of the site; all three of these were taken from deeper soil depths (>6.0 feet). Eachsample had PCB concentrations below the detection limit of 1 ppm (Figure 5).


Twenty-six off-site sediment samples were collected from the drainageways (Figure 5). One sediment sample (0-3 inches) was collected from the north drainageway and ten grab samples (0-3 inches) were collected from the center of the flood control channel. These sample results canbe found in Table 4. At each of five locations in the flood control channel, a sample was taken from the edge of the east bank, the center of the channel, and from the edge of the west bank. These samples were collected using a tube sampler; the depth of each sample was approximately 0 to 2 feet. In two of the samples PCBs were found at concentrations above HAC values.

Off-site Drinking Water Wells

Four off-site water wells located within a two mile radius of the site were sampled in 1984(Figure 3). Two wells supply water to mobile home parks. One of these wells is one mile southof the Geneva site and information on depth was not available. The second well is one milesouthwest of the Geneva site and is screened to approximately 90 feet.

A third well, approximately one and three/quarter miles east northeast of the Geneva Industriessite, supplies water to the City of South Houston and is screened to 951 feet. The fourth waterwell is an active domestic well one-tenth of a mile south southwest of the site and is screened at100 feet.

Each water sample was tested for the presence of PCBs; the domestic water well immediatelysouth of the site was also checked for the presence of volatile organic compounds. PCB levelsin the four water well samples were below detectible limits of 10 ppm; no volatile organiccompounds were detected in the domestic well. These wells showed no contamination.


Eleven off-site groundwater monitoring wells were installed. Two of these were screened in the100-foot sand; the other nine were screened in the 30-foot sand. Contaminants were detected inboth shallow (30-foot sand) and deeper (100-foot sand) groundwater. The off-site 30-foot sandcontaminants (which exceeded HAC values) included PCBs, fluorene, benzo(k)fluoranthene, and2,4 dinitrotoluene (Table 8). Benzo(a)pyrene exceeded HAC levels in the 100-foot sand. Chemicals of concern in the 30-foot sand extend east of the Geneva Industries site (Figure 6).

Fish and Crawfish

Fish and crawfish samples were collected at three sampling locations within the flood controlchannel during July, 1984. One sampling location was upstream of the site; the second locationwas immediately downstream of the main outfall from the site into the flood control channel. The third sampling location was an unspecified distance downstream of the site. Samples wereobtained with baited traps. PCBs were found in tissues of fish and crawfish sampled from themain outfall and downstream of the main outfall (Tables 9a & 9b). Samples of fish and crawfishcaught upstream of the site did not contain PCBs. The detection limit was 0.1 mg/kg.

Table 8.

Geneva Industries Off-site Groundwater Contaminants of Concern
Date SampledSample Depth
Maximum Conc.
LocationHAC VALUES (ppb)Source
Total PCBs7/8430950 GW10,MW120.050.0045EMEG/CSF
Acenaphthylene6/84303MW17, GW28NANANA
Benzo(a)pyrene6/841002MW21, GW420.2NAPMCL
Chrysene6/843070MW12, GW160.2NAPMCL
Fluorene 6/8430800 MW12, GW16 400NARfD
Naphthalene6/8430720 MW12, GW16NANANA
Phenanthrene6/8430220MW12, GW16NANANA
2, 4 dinitrotoluene6/8430120MW1220NAEMEG

NA = No HAC Values Available

Table 9a.

Geneva Industries Total PCB's Fish Samples Flood Control Channel
Date SampledLocationMaximum Value
HAC VALUES (mg/kg)Source
Total PCBs
Maximum Conc.

NA = No HAC values available

Table 9b.

Geneva Industries Total PCB's Crawfish Samples Flood Control Channel

Date SampledLocationMaximum Value
HAC VALUES (mg/kg)Source
Total PCB's
Maximum Conc.

NA = No HAC values available

Other Sources of Off-site Contamination

A search of the 1987, 1988, and 1989 Toxic Chemical Release Inventory (TRI), a USEPAdatabase, revealed other local (zip code) releases of chemicals similar to those found on site. Data contained in the TRI are submitted to USEPA by industrial facilities in compliance withSection 313 of the Emergency Planning and Community Right-to-Know Act of 1986. Table 10contains a list of these contaminants and the reported amounts released for each of the threeyears. The contaminants include Volatile Organic Compounds, biphenyls and napthalene. Norelease of PCBs was reported.


Analytical Petroleum Research Laboratories for IT Corporation used approved methodologies forthe analyses of samples for PCBs. These included comparisons against known standards in eachrun, one in ten sample duplicates and a quarterly methods review against known spike samples. A spike sample is a sample to which a known amount of a specific chemical is added to test theappropriateness of the specific testing method with that particular type of sample. Appropriateness is determined by measuring percent recovery of the chemical added. ITAnalytical Services' (ITAS) Murrysville Laboratory used USEPA approved analytical proceduresin their analyses. References are given in the Site Investigation Volume II, Appendix F. AUSEPA Data Review Summary was not available. Although duplication of results and percentrecovery of spikes were variable, it is assumed that adequate quality assurance and qualitycontrol measures were followed. The analysis and conclusions of this Health AssessmentAddendum are valid only if the referenced information is complete and valid.


During our drive-by site visit, we did not notice any physical or other hazards on the site.

Table 10.

Chemical Releases near the Geneva NPL Site
1987, 1988, 1989 Toxic Chemical Release Inventory
Chemical/ContaminantSource of ReleaseAmount of Annual ReleaseMethod of Release
1987BenzeneTexas Petrochemicals Corp.268 lbsnon-point air
Xylene (mixed isomers)Mobay Synthetics Corp.19,044 lbsnon-point air
1-499 lbspoint air
TolueneMobile Chemical Company
(Houston Olefin Plant)
1-499 lbsnon-point air
1-499 lbspoint air
1-499 lbswater
Ethylene14,000 lbsnon-point air
61,000 lbspoint air
Benzene1-499 lbsnon-pointair
2,300 lbspoint air
1988BenzeneTexas PetrochemcialCorp.200 lbsnon-pointair
Xylene (mixed isomers)Mobay Synthetics Corp.19,004lbsnon-pointair
1-499 lbspoint air
TolueneMobil Chemical Company5,500 lbsnon-pointair
1-499 lbspoint air
220,000lbspoint air
Benzene8,000 lbsnon-pointair
500-999lbspoint air
1-499 lbswater
1989BenzeneTexas PetrochemicalCorp.200 lbsair
Xylene (mixedisomers)Mobay Synthetic Corp.19,004lbsair
TolueneMobil Chemical Company5,450 lbsair
250 lbswater
250 lbswater
Xylene (mixedisomers)Lyondell PetrochemicalCompany269,445lbsair
Biphenyl1,250 lbsair
Naphthalene4,478 lbsair
Ethylene7,213 lbsair


To determine whether people have been, are, or will be exposed to contaminants from the site,we evaluate the environmental and human components that lead to human exposure. Thispathway analysis consists of five elements: a source of contamination, transport through anenvironmental medium, a point of exposure, a route of human exposure, and an exposedpopulation. For a person to be exposed to a contaminant, the exposure pathway must becompleted. An exposure pathway is considered completed when all five elements in the pathwayare present and exposure has occurred, is occurring, or will occur in the future.

Exposure pathways can also be potential or eliminated. A potential pathway is missing at leastone of the five elements and may not be completed in the future. Eliminated pathways aremissing one or more elements and will never be completed. Table 11 identifies the completedand potential pathways. The following discussion incorporates only those pathways which arerelevant and important to the site.

Table 11.

Exposure Pathway Elements
Pathway NameSourceEnvironmental MediaPoint of ExposureRoute of ExposureExposed PopulationTime
SoilTanks, Lagoons, Diked Tank, Drum Storage AreaSurface SoilOn-siteIngestion,
Skin Contact
On-site workersPast
SedimentTanks, Lagoons, Diked Tank, Drum Storage AreaSedimentDrainageways, Flood Control ChannelIngestion,
Skin Contact
Children playing in drainageways & Flood Control ChannelPast
AirTanks, Lagoons, Diked Tank, Drum Storage AreaAirOn and Off siteInhalationWorkers and local residentsPast
FishTanks, Lagoons, Diked Tank, Drum Storage AreaFishDownstream FishingIngestionPersons eating fish from downstream watersPast
GroundwaterTanks, Lagoons, Diked Tank, Drum Storage AreaWaterWater supply wellsIngestion,
Local ResidentsFuture



Based on soil samples taken from the site, past exposure to site contaminants has occurredthrough ingestion of and skin contact with contaminated soils. Exposure to site contaminantsmay also have occurred through the inhalation of contaminated airborne particles. The exposedpopulation consists of former employees who worked on the site before 1967 through 1982. Wedid not consider persons who worked on-site during the planned removal and remedial actionactivities to be exposed since these workers wore protective gear. The main contaminants towhich persons may have been exposed include PCBs, PAHs and TCDDe. Since there was noinformation as to the number of workers on the site during the time the site was active, we wereunable to estimate the total exposed population for this pathway.



In the past, children who came into contact with contaminated sediments may have been exposedto site contaminants. This may have occurred from 1967 until the removal of contaminated soilsand capping of the site was completed in 1990. Since there is only anecdotal evidence(Reference 2) that children played near the flood control channel, we are only considering this a potential pathway. The main contaminants of concern include PCBs and benzo(a)pyrene (aPAH). We were unable to estimate the number of potentially exposed children for this pathway.


Pre-remedial workers and local residents may have been exposed to site contaminants bybreathing contaminated air during the time the site was active. However, the lack of historicalambient air data prevented us considering this a completed exposure pathway.

Ambient air measurements collected during planned removal actions suggest that soil excavationmay have caused PCBs to be released into the air (bound to particulates). However, we did notconsider workers who worked on the site during the planned removal and remedial actionactivities to have been exposed since they were required to wear protective equipment.


Fish and crawfish sampled downstream from the site were contaminated with PCBs. The typesof fish sampled are small and not of the varieties used for human consumption. Exposure to sitecontaminants could have occurred if contaminants in these fish bioaccumulated in the larger fishfound in the bayous downstream.

Although we have included this as a potential exposure pathway, we consider the completion ofthis pathway to be remote. Stormwater runoff from the Harris County flood control channelenters Berry Bayou, then Sims Bayou, over one mile northeast of the site. Generally the floodcontrol channel contains only small quantities of water and has intermittent flow. The likelihoodof contaminated minnows swimming a mile downstream to fishable waters does not seem likely. It is also not likely that the flood control channel could support an edible quality and quantity ofcrawfish.


Future exposure from the ingestion of groundwater is possible if the contaminants are allowed tomigrate towards drinking water supply wells. Groundwater beneath this site generally moves in awest-southwest direction. There are three drinking water wells southwest and south of the sitewhich could be affected. Because contaminants in the groundwater have not reacheddowngradient drinking water wells, people are not drinking contaminated water. Although weare considering this to be a potential exposure pathway, the planned remediation of thegroundwater should make the completion of this pathway unlikely. In the absence ofgroundwater remediation the potential contaminants of concern through this pathway includePCBs, benzo(a)pyrene, 2,4- dinitrotoluene, naphthalene, TCE, mercury, TCDDe, fluorene, andbenzo(k)fluoranthene. The potentially exposed population would include residents from twomobile home parks south and southwest of the site who drink the water, as well as residentsimmediately south of the site who use well water.



In this section we will discuss the possible health effects that may result from exposure tospecific contaminants, evaluate state and local health data bases, and address specific communityhealth concerns.


To evaluate non-carcinogenic health effects, ATSDR has developed Minimal Risk Levels(MRLs) for contaminants commonly found at hazardous waste sites. The MRL is an estimate ofdaily human exposure to a contaminants below which non-cancer, adverse health effects are notexpected to occur. In the event that an MRL is not available, other health effects screening levelssuch as USEPA's RfD may be used. MRLs are developed for each exposure, such as ingestionand inhalation, and for different lengths of exposure, such as acute (less than or equal to 14 days),intermediate (15 to 364 days), and chronic (365 days or more). ATSDR presents these MRLs inToxicological Profiles. These chemical-specific profiles provide information on health effects,environmental transport, human exposure, and regulatory status. These ATSDR ToxicologicalProfiles are used in the following discussion. To evaluate carcinogenic health effects, theUSEPA has developed chemical-specific cancer slope factors (CSF) for contaminants commonlyfound at hazardous waste sites. These CSFs are used to estimate the increased chance that aperson exposed to site contaminants will develop cancer over the course of a lifetime.

Standard exposure scenarios for both children and adults were evaluated for each of thechemicals below using the highest concentrations found in the media of concern. We assumedthat children weigh 16 kilograms, drink 1 liter of water per day, and eat 200 mg of soil per day. Adults were assumed to weigh 70 kilograms, drink 2 liters of water a day, and eat 50 to 100 mgof soil per day. For worker inhalation exposure, we assumed they inhaled 23 cubic meters of airper day. Exposure scenarios were developed for each of the exposed populations. A typicalworker scenario assumed an exposure of 5 days per week for 50 weeks per year for 10 years. Atypical child scenario for exposure to contaminated sediments assumed that the child played inthe sediments 2 days per week for 20 weeks per year for 2 to 10 years. For non-carcinogenichealth effects the dose was averaged over the number of years of exposure. For carcinogenichealth effects the dose was averaged over a lifetime (70 years).

The following contaminants were chosen for evaluation of potential toxicological effects. PCBsand TCDDe were chosen because they were present in completed exposure pathways atconcentrations which exceeded HAC values. PAHs were chosen because they were present incompleted pathways and no HAC values were available.

Polychlorinated biphenyls (PCBs)

Exposure to PCBs has occurred in the past through skin contact with and ingestion ofcontaminated soil. Potential exposure to these contaminants may also have occurred throughinhalation of contaminated air. The main persons potentially exposed to these chemicals includechildren who periodically played in the off-site drainageways and persons who worked on the siteduring the time the site was active.

There is a lack of available toxicological data pertaining to human exposure to PCBs; however,an abundance of animal data suggest that exposure to these chemicals could result in adversehealth effects. Based on animal research, ATSDR has identified a chronic MRL of 0.005µg/kg/day (microgram chemical per kilogram body weight per day) for immunological effectsfrom oral exposure to PCBs (Reference 8). We evaluated exposure scenarios for on-site workersand for children who may have played in the drainageways and estimate that for on-site workersthe chronic MRL was exceeded; therefore, adverse non-carcinogenic health effects are possible.

Potential exposure to PCBs may also have occurred to on-site workers through the inhalation ofcontaminated air. The inhalation of PCBs could cause adverse health effects. There are weak,poorly controlled studies indicating that workers exposed to concentrations ranging from 7 to11,000 µg/m3 reported respiratory tract or eye irritation, coughing, chest tightness, abdominalpain, vomiting, and loss of appetite. Other studies have reported chest pain and decreased serumthyroxine (T4) in workers exposed to PCB concentrations ranging from 0.01 to 12 µg/m3. However, since these workers were also exposed to other contaminants such as trichlorobenzene,the adverse effects could not be attributed to PCBs. Other dermal effects reported in workersinclude skin rashes, pigmentation disturbances of the skin and nails, erythema and thickening ofthe skin, and burning sensations. In these studies, the workers were exposed to various PCBs atlevels as low as 3 µg/m3 for over five years. The lack of historical ambient air data from the timewhen the site was active prevent us from evaluating the potential for adverse health effects frominhalation exposure to PCBs at this site.

Although the highest reported on-site ambient air PCB concentration, measured during plannedremoval actions, was high enough to cause adverse health effects, the workers who would havebeen exposed to this level wore protective equipment. Since all ambient air measurements weretaken within the site boundaries, it is impossible to estimate off-site exposures.

Although there is no direct evidence associating oral exposure to PCBs with the development ofcancer in humans, animal studies have shown ingestion of this compound to cause cancer of theliver in animals. Using USEPA's cancer slope factor for ingestion and exposure scenariosappropriate to the exposed populations, we estimate on-site workers to have no apparentincreased lifetime risk for developing cancer.

Based on available information, adverse noncarcinogenic health effects from past exposure toPCBs at the Geneva Industries site are possible. Adverse carcinogenic health effects fromexposure to PCBs at this site are unlikely. The population at greatest risk for adverse healtheffects are persons who worked at the site during the time the site was active.

Polycyclic Aromatic Hydrocarbons (PAHs)

Potential exposure to PAHs such as chrysene, phenanthrene, benzo(a)pyrene,benzo(k)fluoranthene, and acenaphthylene may have occurred through ingestion of and skincontact with contaminated soil and sediment. Currently neither ATSDR nor the USEPA havehealth-related criteria or guidelines for these contaminants, therefore we were not able evaluatethe potential for adverse health effects from exposure to these contaminants.

When PAHs are applied to the skin of test animals, severe rashes develop. The same sort ofreaction has been noted in humans. Exposure to some PAHs through skin contact and inhalationmay result in increased incidence of skin and lung cancers. Studies of workers have indicatedincreased mortality from lung cancer after exposure to coke-oven and roofing tar emissions. Exposure to PAHs has also resulted in decreased fertility in animal studies. Although many ofthese compounds are considered carcinogens, no carcinogenic comparison values are available toestimate cancer risk.

As of this time, we are unable to draw any inferences on the likely adverse health effects thatmay result from exposure to these contaminants. However, the completion of the sourceremediation program has eliminated the possibility of exposure to these compounds throughcontact with soil and sediment.


Exposure to TCDD in the past has occurred through skin contact with and ingestion ofcontaminated soils. Since TCDD is poorly absorbed through the skin when carried in soil, thelikelihood of exposure through this route is remote. The exposed population includes on-siteworkers.

ATSDR has established a chronic oral MRL of 0.000001 µg/kg/day for TCDD. Using anexposure scenario appropriate to the workers, we estimate that exposure to this chemical wasbelow the MRL. Ingestion of TCDD has also been shown to cause cancer in laboratory animals. Based on these studies, the National Toxicology Program has stated that TCDD is reasonablyanticipated to be a carcinogen. Using the cancer slope factor for TCDD developed by the Foodand Drug Administration and an exposure scenario appropriate to the workers, we estimate thereis no apparent increased lifetime risk for developing cancer (Reference 9).

Based on available information, carcinogenic and non-carcinogenic adverse health effects fromexposure to TCDD at the Geneva Industries site are unlikely.


Because of the possible exposures at this site, we attempted to obtain cancer mortality data forthe surrounding communities from the Texas Department of Health Cancer Registry Division. For reasons mentioned previously in the Health Outcome Data subsection, these data were notavailable. No other health outcome data were available for evaluation. Evaluation of healthoutcome data should be done in the future as need dictates and data become available.


1. Could site contaminants affect the City of South Houston well located approximately1,300 feet east of the site?

It is unlikely that the City of South Houston drinking water well would be affected by the sitecontaminants. Site contaminants were found in groundwater both on and off the site. However,since the direction of groundwater flow is in a west-southwest direction, groundwater and isflowing away from the City of South Houston well. In addition, the City of South Houstondrinking water well is at a depth of 1,067 feet located in the Evangeline aquifer and thecontamination is found in the 30- and 100-foot aquifers only. The selected remedy includesrecovery and treatment of contaminated groundwater from both the 30- and 100-foot sands.


Should residents be concerned about their children playing in the drainage ditches whichreceive stormwater run-off from the site?

PCBs were reported in the drainageways adjacent to the site. However, based on availableinformation, the level of exposure would be unlikely to cause adverse health effects in childrenplaying there. Increases in the amounts of PCBs in the drainageways should not occur sincecontaminated soils have been removed from the site and a capping system has been installed. Previously these soils could have been washed off of the site and into the drainageways duringheavy rains.

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  1. A
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  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #